1. Field of the Invention
The present invention relates to an ink jet printer with an improved print head cleaning apparatus and method of operating the same. More particularly, the present invention relates to an ink jet printer with an improved print head cleaning apparatus and method of operating the same, in which a contact position between a print head and a wiper is periodically changed, thereby preventing abrasion of the wiper and enhancing a wiping effect of the wiper.
2. Description of the Related Art
As a general rule, ink jet printers are designed so that a carriage with an ink cartridge is movably installed to a main frame. The carriage is reciprocated by a moving unit, with support on a timing belt and a guide shaft.
The ink cartridge is provided with a print head on a lower side thereof. The print head sprays ink on printing paper fed by a feeding roller, thereby generating an image. The print head sprays the ink on one side of the printing paper through an injection nozzle, and thus the ink transferred into the printing paper forms an image. Operation of spraying the ink through the injection nozzle is appropriately controlled according to image information received at a controller of the printer.
After printing, residual ink is found in the injection nozzle. Sometimes, especially after the printer has been idle for a long time, the residual ink in the injection nozzle becomes solidified. In this case, the injection nozzle is entirely or partly clogged by the solidified ink. As a result, a proper amount of ink is not sprayed during printing, which results in poor print quality.
The ink injection nozzle may be clogged by the ink as well as by a foreign material such as dust. Dust will also negatively affect print quality. Therefore, to prevent the ink injection nozzle from being clogged, a device for cleaning the print head is required.
Such a print head cleaning apparatus is disclosed in Japan Patent Publication No. 2001-18407 (publication date: Jan. 23, 2001; title: INK JET PRINTER), the entire contents of which are incorporated herein by reference.
As for its configuration, a nozzle head wiper holding member is mounted to a wiper carrier capable of reciprocating in the main scanning direction of a nozzle head in such a manner that the nozzle head wiper holding member can be vertically moved through a predetermined range. A spring for upwardly urging the nozzle head wiper holding member is provided between the wiper carrier and the nozzle head wiper holding member. Both elastically deformable nozzle head wipers, and a wiper contact angle adjusting roller rotatably engaged with the nozzle head side are attached to the nozzle head wiper holding member. The nozzle head is capable of being wiped by holding a contact angle of each of the nozzle head wipers with respect to the lower surface of the nozzle head to a constant level.
One example of the conventional print head cleaning apparatus is shown in FIG. 1. As shown, the device includes a housing 10 installed on the lower side of a cartridge 1, a plate 11 slidably mounted in the housing 10, and a wiper 13 vertically provided on the plate 11. The wiper 13 cleans a print head of the ink cartridge at a home position while it is reciprocated by the plate 11.
The conventional print head cleaning apparatus brings the print head into contact with the wiper at a single position at all times. For this reason, the wiper is subjected to concentrated abrasion at only that single position, thus decreasing wiping efficiency.